Bearing means for reducing wireline friction in flow line loops



Feb. 24, 1970 w. B. WEAVER 3,496,998

BEARING MEANS FOR REDUCING WIRELINE FRICTION IN FLOW LINE LOOPS Filed Dec. 28, 1987 2 Sheets-Sheet l WILLIAM B. WEAVER INVENTOR.

ATTORNEY Feb. 24, 1970 w, WEAVER 3,496,998

BEARING MEANS FOR REDUCING WIRELINE FRICTION IN FLOW LINE LOOPS Filed Dec. 28, 1967 2 Sheets-Sheet 2 FIG. 7

WILLIAM B. WEAVER INVENTOR.

ATTORNEY United States Patent U.S. Cl. 166-.5 8 Claims ABSTRACT OF THE DISCLOSURE This invention concerns the use of wireline tools for use in working over offshore wells completed on the bottom of a body of water with TFL (through flow line) equipment. When using wireline equipment with the TFL equipped well, a train of bearing elements is pumped through the hydraulic lines with the wireline workover elements. Releasable locking mechanisms are provided so that the train of bearing elements will stay in the loop itself during the workover operations. The wireline is then moved along the bearing elements to reduce any friction which would otherwise be caused by the flow line loops.

This invention relates to completion techniques for wells completed beneath a body of water. It relates especially to improved system for improving operations in wireline tools through such wireline completions.

Background A recent development in offshore well completion is the completion of such wells where the well assembly and production control units are positioned beneath the surface of a body of water, and preferably close to the bottom of the body of water. This is in contrast to another procedure for completing offshore wells in which a stationary platform is erected which is supported by the ocean bottom and extends to above the surface of the water. If the platform system is used, the completion procedure can be quite similar to those used on dry land. However, when the Well head assembly is placed on the ocean floor a new set of problems is raised with regard to carrying out workover operations, maintenance or other operations in a completed well. In order to carry out some of the more simple workover operations, such as perforating a well casing, or moving paraffin, it has become necessary to develop an entirely new line of well tools which can be pumped through a production line from some remote location which may be a mile or more away. These tools enter the well by passing down the tubing string to be subsequently selectively positioned to carry out the selected operations. After completing the operation the tool in the tubing string within the well is ordinarily removed by a reverse circulation operation. These tools and techniques are commonly called TFL (through flow line) type operations or tools because they are pumped down through the production string. In order to accommodate TFL tools, the subsea walls are provided with loops in the flow lines which ordinarily take the shape of a segment of a circle having a radius of about feet. The vertical flow tubing in the well is essentially tangential to this loop. There has been considerable literature on this type operation. Further, commercially available tools can be readily obtained, for example, from Otis Engineering Corporation, Dallas, Tex.

Although there has been considerable effort expended to date in developing hydaulic TFL equipment, it is evi- 3,496,998 Patented Feb. 24, 1970 dent that in certain situations the use of conventional wireline techniques will be necessary in underwater completion operations. It has been found one drawback to TFL wireline operations is the power that is lost due to friction in flow line loops. This invention relieves this drawback.

Brief description of the invention A train of bearing elements is placed about the wireline which is used for lowering the wireline tools. The bearing elements are either segmented or otherwise made sufficiently flexible so that the train can take the shape of the ordinary flow line loop at the well head. The leading end of the train is provided with a latching element for releasably latching the train in the flow loop. The flow line loop is provided with an internal latching groove for receiving the dog means of the latching means of the train of bearing elements.

In operation the wireline workover tool enters the flow line and is pumped together with the train of bearing elements down the flow line. The wireline tool is ordinarily a type which can be pumped hydraulically, that is, its outer surface forming sufficient seal with the flowing to be readily pumped. When the train of elements completely enters the How line loop, the bearing train is stopped or tarpped therein. The workover tool is then pumped on down the borehole to its selected position. As the wireline does not touch the walls of the loop of the fiow line but instead contacts only the bearing surface, there is no appreciable friction loss by the wireline passing through the loop. When the workover job is completed the workover tool is removed by winding up of the Wireline at the surface, the striking of the latching means by the workover tool unlatches the tarin of bearings which are then removed with the workover tool.

Various other objects and a better understanding of the invention can be had with the following description taken in conjunction with the drawings in which:

FIGURE 1 illustrates an underwater well completion system for use with TFL tools and modified in accordance with this invention;

FIGURE 2 illustrates a train of bearing elements;

FIGURE 3 illustrates a portion of one segment of the tarin of elements of FIGURE 2;

FIGURE 4 illustrates a cross-section along the line 44 of FIGURE 3;

FIGURE 5 illustrates a typical connection between different segments of the train of FIGURE 2;

FIGURE 6 illustrates a typical releasably latching mechanism of the locking mechanism of the train of hearing elements of FIGURE 2;

FIGURE 7 illustrates a segmented Teflon-lined sleeve for providing a bearing surface for the wireline;

FIGURE 8 illustrates a continuous train of Teflon type bearing.

FIGURE 1 illustrates a subsea well head assembly shown positioned beneath the surface 10 of a body of water and on the ocean floor 12. The well head apparatus includes a platform or anchor base 14 sitting on the ocean floor and connected to the top of the surface of casing 16 which extends into the earth beneath the body of water and is cemented therein in a conventional manner. A housing 18 sits on top of anchor base 14 and encloses various control valves and other well head equipment normally used in a well of this type. The explanation of such control equipment is not necessary for an understanding of this invention as such are well known. The top of the housing 18' is provided with a smaller extension 20 having a valve 22. These can be used for entry into housing 18.

Shown entering extension 20 are two flow lines 24 and 26. These extend from the well head to some remote terminal which may be as much as a mile or more away. The portion of these lines which enters the well head assembly can be called loops 26A and 24A. These loops ordinarily have radii of at least about 5 feet, which are normally sufficiently large to permit the passage of the recently developed TFL tools therethrough withont being caught. These systems are discussed in the prior art; for example, in the ASME publication article Pumpdovm Completion and Workover Techniques for Satellite Underwater Wells, given at the Petroleum Mechanical Engineering Conference, Sept. 17, 1967.

I shall now discuss the modification of the loops and tubing strings 32 and 34 as required for use in the present invention. This includes an enlarged wall portion 28 placed in the well head adjacent the loop' 24A. The internal bore of enlargement 28 is generally the same diameter and mates with the internal diameter of the loop 24A and the string of tubing 34. There is one difference, however. This enlarged portion contains an internal latching groove 30, shown in single line in the cut-away portion of FIGURE 1. The groove is sufliciently short that any tools pumped therethrough will not lose their seal with the wall in passing over such grooves. This groove 30 is wide enough to receive a latching dog. Further, it is wider (or longer along the length of the pipe) than the ordinary space left between the ends of joints of pipe in the connecting collars. This last feature is to prevent the latching dogs of the bearing train from prematurely latching in the flow line before it reaches the flow loop.

Loops 24A and 26A communicate respectively with the tubing strings 32 and 34, respectively. These are parallel tubing strings which are used with normal TFL operations. Such tubing members are connected by Y connections and cross-over ports, landing nipples, etc., (not shown) for use in revers circulation to remove the TFL tools, etc., which is also well known to those skilled in the art.

Attention is next directed to FIGURE 2 which illustrates a train of bearing elements. The bearings are shown in the shape of a flow line loop such as loop 24A of FIGURE 1, but for clarity the flow line loop is not shown. This includes bearing elements 36 with spacers 38 therebet-ween. One end of the device is provided with a releasably locking mechanism 40. Mechanism 40 can incorporate a mechanical jar for use in aiding in the removal of the hearing. The various segments of the train in FIGURE 2 are loosely connected so that the train can take the configuration of the pipeline loop 24A, for example. One way of connecting the segments is shown in FIGURE 5. Spacers 38 are provided with J-shaped slots 42 into which arms 44, on segment 36, loosely fit. The other end of arms 44 can be ball jointed to the housing of the bearing elements 36, for example. Other type connections can be used so long as they permit the segments to take the contour of the loop 24A.

FIGURE 3 illustrates a portion of one bearing segment having shell 46. Cable 50 attached to a wireline tool passes axially therethrough. FIGURE 4 illustrates a cross-section on the line 44 of FIGURE 3 and in this embodiment shows the bearings 48 as roller bearings supported by axes 80 which are supported from webs 82 which are welded or otherwise secured to the shell or housing 46. The cable 50 is supported within the space between the roller bearings 48. This arrangement of the roller bearings is such that it does not require accurate orientation because there are bearings on all sides of the wireline 50.

Attention is next directed to the latching mechanism 40. One suitable system is shown in FIGURE 6. Shown therein is a modified U-shaped lever 56 pivoted at pivot 58. Pivot 58 is supported within the hollow portion 60 in the Wall of latching mechanism 40. One leg of the U is bent outwardly at arm 62 and is urged by spring 64 beyond the wall of housing 40A of the locking mechanism 40. The other leg of U 56 extends beyond the end 66 of latching housing 40A. This has a shoulder 68. When the tool is pumped into the hole, spring 64 urges the latching arm 62 outwardly against the wall of the tubing. The face of shoulder 62A of arm 62 is of suflicient width so that it cannot enter space between any tubing joints which might not be completely made up. As the tool is pumped through the tubing it eventually reaches loop 24A. When latching shoulders 62A reach latching slot 30, they immediately engage therein, locking the train of bearing elements in the loop 24A. The lower end of wire 50 is connected to a workover tool 51. This tool 51 is connected to the train by a shear element, not shown. The shear element is sufiiciently strong to pull the train of bearing elements into the flow line. However, when the locking mechanism 40 is entrenched in groove 30, continued pumping of fluid into tool 51 creates sufficient force to shear the shear element. Then additional pumping of hydraulic fluid through tubing 24 drives the tool 51 to its proper depth. There the workover is performed. After the completion of such workover performance, line 50 is reeled in. Eventually tool 51 contacts releasing lever 68 of the releasing mechanism. This releases arm 62 from groove 30. Then the train of bearing elements is removed with the workover tool 51.

A modification of the bearings of FIGURE 2 is shown in FIGURE 7. This includes a segment 70 which is provided with an axially aligned tubing 72 which is sup ported from the shell of segment 70 by webbing 71. Fluid can readily pass through the openings in webbing 71. The interior of the tubing 72 is lined with a Teflon sleeve 74. The cable 50 passes through this Teflon tube which acts as the bearing surface therefor.

Another modification of a Teflon bearing shown in FIGURE 8 includes a long flexible cylindrical member 84 which can be pumped into the flow line 24, for example. This cylindrical member 84 is provided with a bore 86 in which is placed wireline 88. The outer circumference of elongated Teflon bearing member 84 is serrated as at 90 to facilitate bending when the bearing element enters the flow line loop 26A. The downstream end of bearing element 84 is provided with outwardly biased spring arms 92. The extreme end 94 is curved back toward the center of the flow line. Just before the end 94, the spring has a portion 96 which is curved outwardly but is on too large a radius to lock into the ordinary cracks between the joints of the pipe in the flow line but is sufficiently short to lock into locking groove 30A which is provided at the well head in member 28 as shown in FIGURE 1. Thus bearing member 84 extends around the loop 26A, for example. In operation, the wireline 88 is passed through the bearing member 84 and is attached to a TFL tool in any conventional manner. The pumping of fluid into flow line 24 upstream of the bearing element 84 causes such element to move through the flow line until it is stopped by latching means 96 engaging latching groove 30A. The end 94 shuts against shoulder 99 of groove 30A preventing any further movement. Ordinarily the weight of the workover tool, once it is passed through flow loop 26A, will be sufiicient to cause it to move downwardly into the well bore to its proper position. When it is desired to remove the wireline tool, wireline 88 is taken up at the surface. When the end of the workover tool contacts extension 97 of bearing 84 it pushes such bearing upstream and due to the curvature of springs 92 of the latching portion is unlatched and the bearings train is removed with the wireline tool.

While the above describes the invention in rather detailed form, it is possible to produce various other embodiments without departing from the spirit or scope of the invention.

I claim:

1. A bearing member for use in a subsea well head assembly in which the well head assembly includes dual flow lines, such flow lines having a curved portion adjacent the well head such that TFL pumpdown tools can pass therethrough and latch complementing means supported by said well head assembly adjacent such curved portion, wherein the improvement comprises:

a flexible bearing element train;

there being a longitudinal passage through said bearing element train;

a locking mechanism on one end of said bearing element train for locking with the internal latching complementary means of said circular portion of said flow strings, said locking mechanism being on the end of said bearing element train first inserted into said flow line so that when said locking mechanism is locked to the said internal latching complementary means said flexible bearing element train is in the curved portion of said flow line adjacent said well head.

2. A bearing member element as defined in claim 1 in which said bearing element train is a hollow Teflon tube having a length of about the arc of the said curved portion of said flow line and, further, in which the outer surface of said bearing element has been serrated.

3. An apparatus as defined in claim 1 including a jar means connected to said bearing element adjacent said locking mechanism.

4. A method of placing a workover tool in a well bore in which the well head assembly thereof includes at least two flow lines having curved radii in the vicinity of the well head which comprises:

connecting a wireline to said workover tool;

threading said wireline, upstream of said tool, through a flexible bearing member;

forcing said assembly of said tool and said bearing down one of said flow lines;

locking said bearing member in the curved radius portion of said one flow line near said well head;

thereafter continuing to move said workover downward into said well;

operating said workover tool;

unlocking said bearing and removing said bearing member and said workover tool through said flow line from said well.

5. An apparatus for use in working over subsea Wells having flow lines connecting to the well head and terminating at a remote location, said flow line loops at the point of entry into said well head, each said flow line 6 loop having internal latching slots adpjacent the entry to said well head, which comprises:

a bearing unit having a plurality of bearing elements separated by spacers, said elements and said spacers being flexibly connected together, each said bearing elements having a longitudinal passage therethrough; a locking mechanism connected to the lead end of said bearing unit, said latching mechanism having outwardly biased locking dogs for engaging the latching slot of either of said flow line loops;

10 the outer end of said latching mechanism having tripping members extending therefrom and means interconnecting said members and dogs for unlatching the dogs from said latching slot upon axial force being applied thereto in the direction of said bearing unit.

6. An apparatus as defined in claim 5 including a wireline run through said bearing unit and a workover tool connected to the end of said wireline downhole from said bearing unit.

7. An apparatus as defined in claim 6 in which each said bearing element includes a plurality of roller bearings and means to hold said roller bearings in spaced relation such that the bearing surfaces define an opening concentric with said element, said wireline passing through such opening.

8. An apparatus as defined in claim 5 in which each said bearing element comprises a short cylindrical segment an inner concentric tube, means holding said tube in a concentric position and a Teflon lining coating the interior of said concentric tube.

References Cited UNITED STATES PATENTS CHARLES E. OCONNELL, Primary Examiner JAN A. CALVERT, Assistant Examiner U.S. Cl. X.R. 

